Problem: A goblet contains $8$ red balls, $9$ green balls, and $9$ blue balls. If a ball is randomly chosen, what is the probability that it is not blue?
Answer: There are $8 + 9 + 9 = 26$ balls in the goblet. There are $9$ blue balls. That means $26 - 9 = 17$ are not blue. The probability is $ \frac{17}{26}$.